Abstract:
Growing additional TiO2 thin films on TiO2 substrates in ultrahigh vacuum (UHV)-compatible
chambers have many applications for sample preparation, such as smoothing surface morphologies,
templating, and covering impurities. However, there has been little study into how to control the
morphology of TiO2 films deposited onto TiO2 substrates, especially using atomic layer deposition
(ALD) precursors. Here, the authors show the growth of a TiO2 film on a rutile TiO2(110) surface
using titanium tetraisopropoxide (TTIP) and water as the precursors at pressures well below those
used in common ALD reactors. X-ray absorption spectroscopy suggests that the relatively low sample temperature (175 C) results in an anatase film despite the rutile template of the substrate.
Using ambient pressure x-ray photoelectron spectroscopy, the adsorption of TTIP was found to be
self-limiting, even at room temperature. No molecular water was found to adsorb on the surface.
The deposited thickness suggests that an alternate chemical vapor deposition growth mechanism
may be dominating the growth process. This study highlights the possibility that metal oxide film
deposition from molecular precursors is an option for sample preparations in common UHVcompatible chambers.
